Clear driven oscillating signal light

ABSTRACT

An oscillating signal light mechanism producing substantially constant angular velocity oscillation cycles of a single light is comprised of at least one signal light assembly mounted on a base for rotation of the light assembly relative to the base, a source of motive power including an output shaft rotated at a constant velocity in a single direction of rotation, and a mechanism mechanically connecting the output shaft to the signal light assembly for converting the constant velocity single direction rotation of the output shaft to cycling movements of the signal light assembly through arc segment oscillations at substantially constant angular velocity.

This is a divisional of application Ser. No. 08/006,615; filed on Jan.21, 1993, now U.S. Pat. No. 5,385,062.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention pertains to an oscillating signal light mechanismwhich mechanically produces cycles of substantially constant velocityarc segment oscillations of one or more signal light assemblies.

(2) Description of the Related Art

Signal light mechanisms of the type provided by the present inventionare primarily employed on emergency and service vehicles such as policecars, fire department vehicles and road maintenance trucks. Similarmechanisms have also been employed in flashing light assemblies of othertypes of vehicles and in other applications where it is desired toattract the attention of individuals to flashing light signals fromconsiderable distances.

It has long been recognized that attracting the attention of individualsto the presence of a light signal is more efficiently attained using aflashing light rather than a steady burning light. It is also generallyknown that flashing lights are generated more efficiently throughmechanical motion of a reflector or lens assembly positioned adjacent asteady burning light rather than through electrical current interruptionof a light filament. For many years signal light assemblies employing areflector rotated about a light filament of the assembly, commonlyreferred to as a rotating beacon, have served as a practical means ofproviding visual warning.

A rotating beacon generates a beam signal of essentially constant flashrate and intensity through the entire 360° viewing area of rotation ofthe beam. However, in order for the beam signal generated by therotating beacon to be visible in all directions around the beacon, therotating beacon cannot be used in situations where the rotating beamsignal will be obstructed. For example, when employed on vehicles therotating beacon is typically mounted on the top most portion of thevehicle to avoid the rotating beam of the beacon from being obstructedby any portion of the vehicle. However, many emergency vehicles have aphysical size or shape that prevents the rotating beam of a beacon frombeing seen. To overcome this problem, a multiple of rotating beaconlight assemblies are typically installed on a vehicle so that, incombination, the assemblies provide the required visibility of flashinglight signals from all points around the vehicle perimeter.

However, mounting a multiple of rotating beacon signal light assemblieson a vehicle requires a substantial amount of energy to operate themultiple assemblies. Moreover, that portion of the signal light of eachrotating beacon assembly that is obstructed by a portion of the vehicleserves no signalling purpose and is wasted. To overcome this problem,oscillating signal light assemblies have been developed which employmirrors or reflectors that are oscillated through arc segments that areonly a fraction of the signal light perimeter instead of rotating thereflector and the reflected beam through complete 360° rotations.

For emergency or service vehicle applications, standards have beendeveloped for signal light performance. These standards call for aminimum level of flash energy or intensity, in combination with aminimum and maximum number of flashes per minute visible to a stationaryobserver of the signal. The optimum situation to comply with thestandards is to have a signal light that sweeps through a large arc tobe visible around a large portion of the vehicle's perimeter, where thelight signal swept through the arc has a high level of flash energy orflash intensity that is visible at a high frequency or flashes perminute to an observer positioned stationary along the swept arc.

Prior art signalling devices have been found to be disadvantaged in thesize of the arc swept through by the signalling device. Typically, priorart signalling devices have been limited to angular coverage of about130° and have different angular velocities in different portions oftheir sweep through the arc. The flash energy or intensity of a signallight to a stationary observer increases as the illumination provided bythe light filament increases, but reciprocally decreases as the angularvelocity of the light beam swept through the arc increases. Thus,because the intensity of a signal light is a function of the angularvelocity, the visible warning signal produced by the light is weaker inthe areas of its arc sweep of high oscillation speed, and is higher inthe areas of slow speeds. Studies of oscillating beacon signal lightsindicate that an ideal signal light for use on emergency vehicles wouldbe one which provides about 180° of light beam sweep coverage, atessentially a constant signal flash energy, produced by a constantangular velocity of the signal light beam through the arc sweep of thebeam.

Prior art signalling light apparatus have been developed that arecapable of sweeping a light signal beam through an arc segment atsubstantially a constant angular velocity. However, these types ofsignalling apparatus have required involved electronic circuitry toproduce the oscillating sweep of the signal light beam where thecircuitry employed in the apparatus significantly increases the overallcost of producing the apparatus.

SUMMARY OF THE INVENTION

The present invention provides a simplified oscillating signal lightmechanism where a light beam of a signal light assembly is swept throughan arc segment in substantially constant angular velocity oscillationcycles by solely mechanical means without the need for involved andexpensive electronic circuitry and switching. The signal light mechanismof the invention may be employed as a signal light of emergencyvehicles, and may also be employed in other applications requiring anattention attracting signalling device producing optimum signallingeffectiveness at a minimum of expense.

The oscillating signal light mechanism of the invention is provided infour similar embodiments, each generally comprising a base, at least onesignal light assembly mounted on the base for rotation of the assemblyrelative to the base, a source of motive power including an output shaftrotated at a constant velocity in a single direction of rotation, and amechanical connection between the output shaft and the signal lightassembly converting the constant velocity, single direction rotation ofthe output shaft to cycling movements of the light assembly through arcsegment oscillations at substantially constant angular velocity.

The first embodiment of the invention employs a driven gear having a camsurface formed thereon where the gear is driven by the output shaft in asingle direction of rotation at a substantially constant speed. A linkmember in the form of a second gear is positioned adjacent the drivengear and is provided with a cam follower that engages the cam surface ofthe driven gear. The gear teeth of the second gear mesh with gear teethof a third gear formed on the signal light assembly. Rotation of thedriven gear in the single direction of rotation by the output shaftcauses the cam follower of the second gear to follow along the drivengear cam surface and thereby causes the second gear to oscillate aboutits center axis through an arc segment. The oscillations of the secondgear in turn cause the signal light assembly to cycle through arcsegment oscillations at substantially constant angular velocity. Bysubstituting the gear formed on the signal light assembly for differentgears having different numbers of gear teeth and different diameters,the arc segment through which the light assembly is oscillated may beadjusted.

The second embodiment of the oscillating signal light mechanism of theinvention employs the same driven gear having a cam surface as the firstembodiment. The second embodiment replaces the second gear of the firstembodiment with a link member in the form of a connecting rod. Theconnecting rod pivots about a fixed axis and has a cam follower mountedthereon that engages with the cam surface of the driven gear. Two ormore pulleys are mounted for rotation on the base with at least one ofthe pulleys being mounted on a light assembly which is mounted forrotation on the base. A belt is looped around the pulleys and ispositively engaged to each pulley mounted on a light assembly to avoidrelative slip between the belt and pulley, and an opposite end of theconnecting rod from its pivot point is connected to the belt. Onrotation of the output shaft, the driven gear is again driven at aconstant velocity in a single direction of rotation. The rotation of thedriven gear and the engagement of the connecting rod cam follower withthe driven gear cam surface causes the connecting rod to cycle througharc segment oscillations about its pivot point. The connection of thesecond end of the connecting rod to the belt transmits the arc segmentoscillations of the rod to the pulleys causing the pulleys to oscillatethrough arc segments and thereby causing the signal light to cyclethrough arc segment oscillations at substantially constant angularvelocity. By substituting pulleys of different diameters the arc segmentthrough which the light assembly is oscillated may be adjusted.

The third embodiment of the oscillating signal light mechanism of theinvention employs the same driven gear with a cam surface as the secondembodiment. The third embodiment replaces the pivoting connecting rod ofthe second embodiment with a link member in the form of a linearlyreciprocating slide bar. The slide bar is supported for reciprocatingsliding movement over the gear and cam surface by a pair of guidebushings spaced on opposite sides of the gear. The opposite ends of theslide bar-are connected to the pulley of the second embodiment. A camfollower depends downward from the slide bar and engages in the camsurface of the driven gear. The remaining structure of the thirdembodiment of the invention is substantially identical to that of thesecond embodiment. On rotation of the output shaft, the driven gear isrotated at a constant velocity in a single direction of rotation. Therotation of the driven gear and the engagement of the cam follower ofthe slide bar in the cam surface causes the slide bar to reciprocatelinearly through the guide bushings. The connection of the slide bar tothe belt transmits the reciprocating movement of the bar to the pulleys,causing-the pulleys to oscillate through arc segments and therebycausing the signal light to cycle through arc segment oscillations atsubstantially constant angular velocity. By substituting pulleys ofdifferent diameters, the arc segment through which the light assembly isoscillated may be adjusted.

The fourth embodiment of the oscillating signal light mechanism of thepresent invention employs a first driven gear and a second gear as inthe first embodiment of the invention, however the first and secondgears mesh with each other for rotation about their respective axes inopposite directions of rotation at substantially the same velocity. Thefirst and second gears have arcuate sections of gear teeth formedthereon that extend along only fractions of the circumferences of eachof the gears. The signal light assembly of this embodiment, like thefirst embodiment, also has a third gear formed thereon and the arcsegments of gear teeth of the first and second gears alternately engagewith the gear teeth of the light assembly gear, thereby converting theconstant velocity rotation in a single direction of the output shaft, tocycling movements of the signal light assembly through arc segmentoscillations at substantially constant angular velocity. In the fourthembodiment of the invention the size of the arc segment swept by thesignal light assembly can be adjusted by employing the third gear as anidler gear and providing a fourth gear on the light assembly in meshwith the third gear. Changing the size and number of teeth of the fourthgear will adjust the arc segment of oscillation of the light assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects and features of the present invention are revealed inthe following detailed description of the preferred embodiments of theinvention and in the drawing figures wherein:

FIG. 1 is a plan view of the first embodiment of the oscillating signallight mechanism of the present invention;

FIG. 2 is a front elevation view of the first embodiment of themechanism;

FIG. 3 is a side elevation view of the first embodiment of themechanism;

FIG. 4 is a plan view, in section, of the first embodiment of themechanism taken along the line 4--4 of FIG. 2;

FIG. 5 is an elevation view, in section, of the first embodiment of themechanism taken along the line 5--5 of FIG. 4;

FIG. 6 is an elevation view, in section, of the first embodiment of themechanism taken along the line 6--6 of FIG. 4;

FIG. 7 is a schematic of the cam configuration, and the circumferentialsubdivisions and the arc segment subdivisions through which therespective first and second gears of the first embodiment of themechanism travel in operation of the mechanism;

FIG. 8 is a plan view of the second embodiment of the oscillatingmechanism of the invention;

FIG. 9 is an elevation view of the second embodiment of the mechanism;

FIG. 10 is a plan view of the third embodiment of the oscillatingmechanism of the invention;

FIG. 11 is an elevation view of the third embodiment of the mechanism;

FIG. 12 is a plan view of the fourth embodiment of the oscillatingmechanism of the invention;

FIG. 13 is an elevation view of the fourth embodiment of the mechanism;

FIG. 14 is an elevation view, in section, of the fourth embodiment ofthe mechanism taken along the line 14--14 of FIG. 13; and,

FIG. 15 is a view similar to FIG. 12 but showing the addition of anidler gear.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-6 show the first embodiment of the oscillating signal lightmechanism 22 of the invention. The first embodiment is generallycomprised of a base 24, a light assembly 26, a source of motive power,in this case an electric motor 28, and the inventive mechanical assembly32 of the embodiment operatively connecting the motor 28 to the lightassembly 26.

The base 24 is primarily illustrative in this and the followingembodiments and may be a base of a signal light enclosure or an existingsurface of a vehicle on which the mechanism 22 is employed.

The light assembly 26 is, for the most part, conventional and thereforeis not described here in great detail. The assembly includes a lowerhousing portion 34 mounted to the base 24 by a hollow pivot pin or post36. The post 36 attaches the light assembly housing to the base foroscillating or rotating movements of the light assembly relative to thebase. An upper housing portion 38 is attached to and extends from thelower housing portion 34 and includes a conventional light socket 42with a light bulb 44 received in the socket. Electrical wiring 46 forthe socket 42 extends through the housing portions and the hollowinterior of the pivot post 36 to below the base 24 where it is connectedto a conventional power source (not shown). A support arm 48 extendsupward from the upper housing portion 38 and supports a reflector 52adjacent the light bulb 44.

The motor 28 is a conventional electric motor connected to a separatepower source (not shown). The motor is supported on the base 24 by asupport bracket 54. An output shaft 56 of the motor has a worm gear 58secured thereon. In operation, the worm gear 58 is rotated in a singledirection at a substantially constant velocity by the motor. Inalternate embodiments, the worm gear 58 may be powered by a motivesource completely separate from the base 24.

The mechanical assembly 32 of the invention includes a first driven gear62 mounted for rotation on the base 24 by a first shaft 64 extendingthrough the center of the gear. The first driven gear 62 has a pluralityof gear teeth 66 formed around its circumference and also has a camsurface provided on the gear in the form of a cam slot 68 in the gear'sbottom surface. As is best seen in FIG. 4, the cam slot 68 has a uniqueconfiguration which is generated in a manner yet to be described.

The mechanical assembly 32 also includes a link member in the form of asecond gear 72 mounted for rotation on the base 24 by a second shaft 74extending through the second gear. As shown in the drawing figures, thesecond gear 72 is only a section of a full gear and comprises only anarc segment of gear teeth 76. This enables the mechanism 32 to beconstructed more compactly. However, the second gear 72 may be a fullgear with the second shaft 74 extending through the center of the gearand the gear teeth 76 extending entirely around the circularcircumference of the gear without affecting the operation of themechanical assembly 32. The second gear 72 is provided with a camfollower 78 projecting upward from the top surface of the gear andengaging in the cam slot 68 of the first gear.

The mechanical assembly 32 also includes a third gear 82 secured to thelower housing portion 34 of the light assembly 26 for rotation therewithabout the light assembly pivot post 36. The third gear 82 has aplurality of gear teeth 84 extending around its circumference and thegear teeth 76 of the second gear 72 engage with the third gear teeth 84.In this manner, the second gear 72 serves as the link member between thefirst driven gear 62 and the third gear 82 of the light assembly.

In operation, as the motor output shaft 56 rotates at a constant speedin a single direction, the worm gear 58 rotates the first driven gear 62about the center axis of its shaft 64 in a single direction and at areduced constant speed. Rotation of the first gear 62 about its shaft 64also imparts rotation to the cam slot 68 about the shaft. The rotationof the cam slot 68 about the center axis of the shaft 64 causes the camfollower 78 of the second gear 72 to move through an arc segment havinga constant radius corresponding to the distance of the center of the camfollower 78 from the center axis of the second gear shaft 74. As the camfollower 78 moves through the arc segment, it causes the second gear 72to oscillate about the center axis of the second shaft 74 through thesame arc segment. The meshing engagement of the gear teeth 76 of thesecond gear with the gear teeth 84 of the third gear converts theoscillating movement of the second gear 72 to oscillating movement ofthe third gear 82. The third gear and the attached light assembly 26oscillate through an arc segment about the center axis of the lightassembly pivot post 36 at a substantially constant velocity. In thismanner, the constant speed rotation in one direction of the motor outputshaft 56 is converted to cycling movements of the signal light assembly26 through arc segment oscillations at a substantially constant speed.It should be appreciated that by changing the-diameter of the third gear82, the number of gear teeth 84 around the circumference of the gearwill also change. By substituting the third gear 82 on the lightassembly with a replacement gear having a different diameter and adifferent number of gear teeth around its circumference, and byremounting the light assembly to the base 24 by inserting the lightassembly pivot post 36 in an adjustment hole 86 provided through thebase at the proper spaced position from the gear teeth 76 of the secondgear 72, the arc segment oscillations of the light assembly are adjustedand the speed of the oscillations is also adjusted. In this manner, thearc segment through which the light assembly is oscillated can beadjusted from a fraction of a complete rotation to one or more completerotations.

FIG. 7 schematically shows a preferred configuration of the first drivengear cam slot 68. The slot configuration 92 shown converts the constantvelocity, single direction rotation of the motor output shaft 56 tocycling movements of the signal light assembly 26 through arc segmentoscillations at substantially constant angular velocity. In FIG. 7, thecam slot configuration 92 is divided into a plurality of circumferentialsubdivisions by a plurality of lines 94 radiating from the center axis96 of the first driven gear. Adjacent radial lines 94 are separated byequal angles 98 and the portions of the cam slot configuration 92between adjacent radial lines 94 represent the portions of the firstdriven gear cam slot 68 through which the cam follower 78 travels as thedriven gear 62 rotates through an angle 98 about the center axis of thegear shaft 64. The arc segment 102 represents the complete arc segmentthrough which the cam follower 78 oscillates as the second gear 72oscillates about the center axis 104 of its shaft 74. The arc segment102 is divided into equal arc subdivisions 106, the number of whichequals the number of cam slot circumferential subdivisions 108 aroundone-half of the cam slot configuration 92.

Generally, as the driven gear 62 rotates at a constant speed in onedirection, the rotation of the gear through each circumferentialsubdivision causes a corresponding movement of the cam follower 78 andsecond gear 72 through an arc subdivision 106. Beginning with the camfollower 78 positioned in the cam slot 68 in the position represented bythe point 112 in FIG. 7, as the driven gear rotates clockwise 90° thecam slot 68 also rotates and the cam follower 78 moves through the slotto the point 114 shown in FIG. 7. At this position of the cam slotconfiguration 92, the cam follower 78 is moved through the same numberof arc subdivisions 106 as the number of circumferential subdivisions108 that the follower has passed through due to the configuration 92 ofthe cam slot. Therefore, with the driven gear 62 having rotated throughone-quarter of a complete rotation, the cam follower 78 is oscillatedhalf-way through the arc segment 102 to the point 116 shown in FIG. 7.

As the driven gear 62 continues to rotate an additional 90° so that thegear has now completed one-half of a complete rotation, the cam follower78 is positioned at the point 118 relative to the cam slot configuration92. Having rotated through half of the number of cam slotcircumferential subdivisions 108, the cam follower has simultaneouslymoved through the total number of arc subdivisions 106 to the point 122of the arc. With each of the arc subdivisions 106 being equal in size,as the first gear 62 rotates at a constant speed through one-half of acomplete rotation, the cam follower is pushed by the cam slotconfiguration 92 through the complete configuration of the arc segmentand has caused the second gear 72 to oscillate through one-half of acycle of the arc segment oscillation at a constant speed.

As the first gear 62 continues to complete its rotation and rotates anadditional 90°, the cam follower 78 travels through the cam slot 68 tothe point 124 on the cam slot configuration 92. At this point 124 on thecam slot configuration 92, the cam follower 78 has been pulled backthrough the arc segment to the point 116 of the arc. As the first gear62 completes one complete revolution, the cam follower is positionedagain at the point 112 on the cam slot configuration where rotation ofthe first gear began. At this point 112, one complete cycle of the arcsegment oscillation has taken place at a substantially constant speed.In the preferred embodiment, the ratio of gear teeth between the secondgear 72 and the third gear 82 causes the light assembly to rotate fromits initial position shown in solid lines in FIG. 1, through an arc ofgreater than 180° to a second position shown in dashed lines in FIG. 1,and then back to its initial position.

In some applications, to facilitate production of the driven or firstgear 62, the cam slot configuration could be more simplified by formingit in a more circular configuration 128 as represented in dashed linesin FIG. 7. This circular configuration 128 is empirically formed toapproximate the theoretical, constant speed cam configuration 92 andalso produces a substantially constant speed oscillation of the lightassembly through the arc segment. Alternatively, the slot configurationcould be modified to any one configuration ranging between the optimumconstant speed configuration 92 shown in FIG. 7 and the circularconfiguration 128 if so desired for a particular application.

The second embodiment of the oscillating signal light mechanism 132shown in FIGS. 8 and 9 is similar to the first embodiment in that itemploys a driven gear having the same cam slot configuration of thefirst embodiment. The mechanism of the second embodiment is generallycomprised of a base 134, a pair of light assemblies 136, an electricmotor 138 and a mechanical assembly 142 converting the constant speedsingle direction rotation of the motor to cycles of arc segmentoscillations of the light assemblies. The base 134 and electric motor138 of the second embodiment are substantially identical to that of thefirst described embodiment with the electric motor including an outputshaft and a worm gear 144 mounted on the shaft.

Each of the light assemblies 136 are conventional and are generallycomprised of housing portions 146 mounted to the base 134 by supportbrackets 148 for rotating and oscillating movement of the lightassemblies about their center axes relative to the base. The lightassemblies include light sockets 152 and light bulbs 154 received in thesockets. The electrical wiring 156 providing power to the light socketsfrom separate power sources (not shown) extends from the bottom of thehousings 146 through the base. Both light housings 146 are assembledwith pulleys 158 mounted on the exteriors of the housings. A belt 160 islooped around each of the pulleys 158 a sufficient number of times toensure that at least one point on the circumference of each of thepulleys will remain in engagement with the belt throughout the entireoscillation movements of the pulleys and light assemblies. At the onepoint on the circumference of each of the pulleys where the belt doesnot disengage from the pulleys as they oscillate, the belt is positivelyattached to the pulleys to prevent relative slip between the belt andpulleys during operation of the mechanism and to keep the oscillatingmovements of the light assemblies in synchronism. As shown in FIG. 8,the pulleys 158 have equal diameters and will oscillate their associatedlight assemblies about their center axes through substantially equal arcsegments and at substantially the same speed on movement of the belt.Alternatively, the pulleys 158 are replaceable with substitute pulleyshaving different diameters so that the arc segment through which thepulleys and light assemblies oscillate may be adjusted together with thespeed of oscillation. Moreover, the pulley on one light assembly mayhave a different size diameter than the pulley on the other lightassembly causing the two assemblies to oscillate through different arcsegments and at different speeds of oscillation. Still further, theembodiment of the invention shown in FIG. 8 may be modified withadditional light assemblies other than the two shown so that theplurality of light assemblies will oscillate together. Of course, as thesize and number of the pulleys are changed, the size of the belt loopedaround the pulleys must be correspondingly changed. Each of the lightassemblies also includes a support arm 162 that extends upward from theassembly housing 146 and supports a reflector 164 adjacent the bulb 154of the assembly.

As in the first embodiment, the second embodiment includes a firstdriven gear 166 mounted to the base 134 by a first shaft 168 forrotation of the gear relative to the base about the center axis of theshaft. The first gear has a cam surface provided by a cam slot 172formed in the gear in the same manner as the driven gear of the firstembodiment except that the slot is formed in the top surface of thegear. A plurality of gear teeth 174 surround the circumference of thefirst driven gear and mesh-with the worm gear 144 of the motor. Theconfiguration of the cam slot 172 is identical to that of the firstembodiment. Moreover, the modifications to the cam slot described withreference to the first embodiment of the slot are also possible with thecam slot 172 of the second embodiment of the invention. Like the firstembodiment of the cam slot, the preferred cam slot configuration of thesecond embodiment is also schematically represented in FIG. 7. Theconfiguration of the slot 172 converts the constant velocity, singledirection rotation of the motor worm gear 144 to cycling movements ofthe light assemblies 136 through arc segment oscillations atsubstantially constant angular velocity. Also like the first embodiment,in some applications, to facilitate production of the driven gear 166,the cam slot configuration could be more simplified by forming it in amore circular configuration such as that represented by the dashed line128 in FIG. 7. The circular configuration is empirically formed toapproximate the theoretical, constant speed cam configuration and alsoproduces substantially constant speed oscillations of the lightassemblies through their arc segments. Alternatively, the cam slotconfiguration could be modified to any one configuration ranging betweenthe optimum constant speed configuration 92 shown in FIG. 7 and thecircular configuration 128 if so desired for a particular application.

The second embodiment of the invention does not employ a second gear asthe link member as in the first embodiment, but employs a connecting rod176 as the link member between the first driven gear 166 and the belt160. The connecting rod 176 is mounted to the base 134 at one end by apivot shaft or post 178. The mounting of the first end of the connectingrod 176 to the base by the pivot post 178 enables the rod to oscillatethrough an arc segment about the pivot connection of the rod to thepost. The opposite, second end of the rod is connected to the belt 160.A cam follower 182 is connected to the rod intermediate its oppositeends. The follower 182 extends below the rod and engages in the cam slot172 of the first gear 166.

The operation of the second embodiment of the oscillating signal lightmechanism 132 is substantially identical to that of the first embodimentin that it converts the constant speed single direction rotation of themotor output shaft to cycles of substantially constant velocity arcsegment oscillations of the light assemblies 136. As the motor 138drives the worm gear 144 at a constant speed in a single direction, thefirst driven gear 166 is driven at a reduced constant speed in a singledirection of rotation about the center axis of the gear shaft 168. Thecam slot 172 travels in the same direction of rotation as the first gearand at the same constant speed of rotation of the gear. The cam follower182 engaging in the cam slot 172 causes the connecting rod 176 tooscillate through an arc segment about the pivot post 178 supporting therod. In the same manner as that described above with reference to thefirst embodiment and FIG. 7, as the cam slot 172 completes one rotationabout the gear shaft 168, the second end of the connecting rod 176cycles through one complete arc segment oscillation. The movement of therod second end through the arc segment oscillation imparts motion to thebelt 160 that in turn rotates or oscillates the pair of pulleys 158 andtheir associate light assemblies 136 through arc segments, the size ofwhich is determined by the diameter of the pulleys. Because the motionof the second end of the connecting rod 176 through each of the arcsegment subdivisions is at a substantially constant speed as explainedearlier with reference to the first embodiment, the arc segmentoscillations imparted to the light assemblies 136 by the pulleys-158 andthe belt 160 are also at substantially constant speeds.

The third embodiment of the oscillating signal light mechanism 192 shownin FIGS. 10 and 11 is similar to the second described embodiment in thatit employs a driven gear having the same cam slot configuration of thesecond embodiment to drive a pair of pulleys and their associated signallight assemblies just as in the second embodiment. The mechanism of thethird embodiment is generally comprised of a base 194, a pair of lightassemblies 196, an electric motor 198 and a mechanical assembly 202converting the constant speed single direction rotation of the motor tocycles of arc segment oscillations of the light assemblies. The base 194and electric motor 198 of the third embodiment are substantiallyidentical to that of the second embodiment with the electric motorincluding an output shaft and a worm gear 204 mounted on the shaft, theonly differences being the changed relative position of the motor on thebase.

Each of the light assemblies 196 are conventional and are identical tothe light assemblies of the second embodiment. Like the assemblies ofthe second embodiment, the assemblies 196 include housing portions 206mounted to the base 194 by support brackets 208 for rotating andoscillating movement of the light assemblies about their center axesrelative to the base. Light sockets 208 are supported on the housingportions 206 and light bulbs 212 are received in the sockets. Theelectrical wiring 214 providing power to the light sockets from separatepower sources (not shown) extends from the bottom of the housingsthrough the base. Both light housings 206 are assembled with pulleys 216mounted on the exteriors of the housings. A belt 218 is looped aroundeach of the pulleys 216 a sufficient number of times to ensure that atleast one point on the circumference of each of the pulleys will remainin engagement with the belt throughout the entire oscillation movementsof the pulleys and light assemblies. Like the second embodiment, at theone point on the circumference of each of the pulleys where the beltdoes not disengage from the pulleys as they oscillate, the belt ispositively attached to the pulleys to prevent relative slip between thebelt and pulleys during operation of the mechanism and to keep theoscillating movements of the light assemblies in synchronism. As shownin FIGS. 10 and 11, the pulleys 216 have equal diameters and willoscillate their associated light assemblies 196 about their center axesthrough substantially equal arc segments and at substantially the samespeed on movement of the belt 218. Like the second embodiment, thepulleys 216 are replaceable with substitute pulleys having differentdiameters so that arc segments through which the pulleys and lightassemblies oscillate may be adjusted together with the speed ofoscillation. The pulleys on the two light assemblies may also havedifferent size diameters to cause the two light assemblies to oscillatethrough different arc segments and at different speeds of oscillation.Moreover, the third embodiment of the invention may be modified withadditional light assemblies other than the two shown so that pluralitiesof light assemblies will oscillate together. As the size and number ofpulleys are changed, the size of the belt looped around the pulleys willalso be correspondingly changed. Each of the light assemblies alsoincludes a support arm 222 extending upward from the assembly housing206 and supporting a reflector 224 adjacent the bulb 212 of theassembly.

As set forth above, the third embodiment includes a driven gear 226mounted to the base 194 by a first shaft 228 for rotation of the gearrelative to the base about the center axis of the shaft. A plurality ofteeth 230 surround the driven gear and mesh with the worm gear 204. Thefirst gear 226 has a cam surface provided by a cam slot 232 formed inthe top of the gear with the cam slot-having the same configuration ofthe second embodiment in that it is also schematically represented inFIG. 7. The configuration of the slot 232 converts the constantvelocity, single direction rotation of the motor worm gear 204 tocycling movements of the light assemblies 196 through arc segmentoscillations at substantially constant angular velocity in the samemanner as the second embodiment as will be explained. In the same manneras the second embodiment of the invention, to facilitate production ofthe first gear 226 the cam slot configuration could be more simplifiedby forming it in a more circular configuration as represented by thedashed line 128 in FIG. 7. Alternatively, the cam slot configurationcould be modified to any one configuration ranging between the optimumconstant speed configuration 92 shown in FIG. 7 and the circularconfiguration 128 if so desired for a particular application.

The third embodiment does not employ a pivoting connecting rod as thelink member as in the second embodiment, but employs a linearlyreciprocating slide bar 234 as the link member between the first drivengear 226 and the belt 218. The slide bar 234 is mounted to the base 194at its opposite ends by a pair of guide bushings 236. The slide bar 234extends through the centers of the guide bushings 236 and the mountingof the bar in the bushings enables the bar to reciprocate linearlythrough the bushing centers. The opposite ends of the slide bar 234 areconnected to opposite ends of the belt 218 by a pair of downwardlydepending pins 238. A cam follower 242 is connected to the rodintermediate its opposite ends. The follower 242 extends below the rodand engages in the cam slot 232 of the first driven gear 226 in the samemanner as the cam follower of the second embodiment.

The operation of the third embodiment of the oscillating signal lightmechanism 192 is substantially identical to that of the secondembodiment in that it converts the constant speed single directionrotation of the motor output shaft to cycles of substantially constantvelocity arc segment oscillations of the light assemblies 196. As themotor 198 drives the worm gear 204 at a constant speed in a singledirection, the first driven-gear 226 is driven at a reduced constantspeed in a single direction of rotation about the center axis of thegear shaft 228. The cam slot 232 travels in the same direction ofrotation as the first gear and at the same constant speed of rotation ofthe gear. The cam follower 242 engaging in the cam slot 232 causes theslide bar 234 to reciprocate linearly through the centers of the guidebushings 236 supporting the bar. In the same manner as that describedabove with reference to the second embodiment and FIG. 7, as the camslot 232 completes one rotation about the gear shaft 228, the slide bar234 cycles through one complete linear reciprocation. The movement ofthe slide bar through one complete reciprocation imparts motion to thebelt 218 that in turn rotates or oscillates the pair of pulleys 216 andtheir associated light assemblies 196 through arc segments, the size ofwhich is determined by the diameter of the pulleys. Because thereciprocating motion of the slide bar through each complete linear cycleis at a substantially constant speed due to the configuration of the camslot 232 as explained above with regard to the second embodiment, thearc segment oscillations imparted to the light assemblies 196 by theirpulleys 216 and the belt 218 are also at substantially constant speeds.

The fourth embodiment of the oscillating signal light mechanism 252 ofthe present invention is shown in drawing FIGS. 12-14. This embodimentis similar to the first described embodiment in that it employs threegears in converting the constant speed, single direction rotation of amotor output shaft into cycles of substantially constant velocity arcsegment oscillations of a light assembly.

The mechanism of the fourth embodiment is generally comprised of a base254, a light assembly 256, an electric motor 258 and a mechanicalassembly 262 converting the constant speed single direction rotation ofthe motor to cycles of arc segment oscillations of the light assembly.The base 254 and electric motor 258 are substantially identical to thatof the first described embodiments with the electric motor including anoutput shaft and a worm gear 264 mounted on the shaft.

Again, the light assembly 256 employed with this embodiment of theinvention is, for the most part, conventional. The assembly includes ahousing portion 266 attached to the base by a hollow pivot pin or post268. The post 268 attaches the light assembly housing to the base foroscillating or rotating movements of the light assembly relative to thebase. A conventional light socket 272 is provided extending from anupper portion of the housing 266 and a light bulb 274 is received in thesocket. Electrical wiring 276 for the socket extends through the housingand the hollow interior of the pivot post to below the base where it isconnected to a conventional power source (not shown). A support arm 278extends upward from the housing and supports a reflector 282 adjacentthe light bulb 274.

As in the previously described embodiments, the fourth embodimentincludes a first driven gear 284 mounted to the base 254 by a firstshaft 286 for rotation of the gear relative to the base about the centeraxis of the shaft. The first gear has a plurality of gear teeth 288 thatsurround the circumference of the gear and mesh with the worm gear 264of the motor. The first gear 284 is also provided with an arcuatesection of gear teeth 292 that are extensions of the gear teeth 288 thatsurround the circumference of the first gear. As seen in the drawingfigures, the arc section of gear teeth 292 is positioned on top of thefirst gear 284 above the gear teeth 288 that completely surround thecircumference of the gear, and the arc section of gear teeth 292 extendsless than half way around the circumference of the gear.

The mechanical assembly 262 also includes a second gear 294 mounted forrotation on the base 254 by a second shaft 296 extending through thecenter of the second gear. The second gear is also provided with aplurality of gear teeth 298 that extend completely around thecircumference of the gear. The number of gear teeth in the plurality 298equals the number of gear teeth 288 surrounding the circumference of thefirst gear. The second gear is also provided with an arcuate section ofgear teeth 302 on the top surface of the gear. As with the first gear,the gear teeth of the second arcuate section 302 are extensions of thegear teeth 298 that completely surround the circumference of the secondgear. However, the arcuate section of gear teeth 302 extends less thanhalf way around the circumference of the second gear. As seen in thedrawing figures, the plurality of gear teeth 288 extending around thecircumference of the first gear are in constant mesh with the pluralityof gear teeth 298 extending around the circumference of the second gear.However, the first arcuate section of gear teeth 292 is positioned onthe first gear relative to the second arcuate section of gear teeth 302positioned on the second gear so that the first and second arcuatesections of teeth never come into mesh with each other as the first andsecond gears rotate in mesh with each other.

A third gear 304 is secured to the housing 266 of the light assembly 256for rotation therewith about the light assembly pivot post 268. Thethird gear 304 has a plurality of gear teeth 306 extending completelyaround its circumference. The number of gear teeth surrounding the thirdgear 304 is equal to the numbers of gear teeth surrounding the first 284and second 294 gears. As seen in the drawing figures, the third gear 304is positioned on the light assembly housing 266 where the teeth 306 ofthe third gear mesh with only the teeth of the first arcuate section 292of the first gear and the second arcuate section 302 of the second gear.The teeth 306 of the third gear 304 do not mesh with the gear teeth 288that extend completely around the circumference of the first gear 284 orthe gear teeth 298 that extend completely around the circumference ofthe second gear 294. Due to the relative positions of the first andsecond arcuate sections of gear teeth 292, 302, it can be seen that thefirst and second arcuate sections of gear teeth mesh alternatively withthe gear teeth 306 of the third gear. The numbers of gear teeth and thediameters of the first, second and third gears are specificallydetermined so that the gear teeth of one of the two arcuate sections ofteeth 292, 302 will just be coming into engagement with the gear teeth306 of the third gear as the gear teeth of the other of the two arcuatesections 292, 302 are just coming out of engagement with the gear teethof the third gear.

In the arrangement of the three gears shown in FIG. 12, because each ofthe three gears 284, 294, 304 have equal numbers of gear teeth extendingcompletely around their circumferences and because each of the threegears have equal diameters, the center axes A, B, C of the threerespective gears 284, 294, 304 form the three vertices of an equilateraltriangle shown in dashed lines in FIG. 12. The dashed lines extendingfrom the center of one of the three gears to the centers of the othertwo gears are separated by an angle of 60°. In order to maintain thesynchronous rotation of the three gears and to ensure that the arcuategear teeth sections 292, 302 of the first and second gears alternatelymesh with-the gear teeth 306 of the third gear, the number of gear teethin each gear arc segment that subtends the 60° angle between adjacentsides of the equilateral triangle must be an integer and one-half ofgear teeth. For example, the numbers of gear teeth in the arc segmentsbetween points a and b, b and c, and c and a, must be an integer andone-half of gear teeth. In the operative environment shown in FIG. 12,the number of gear teeth in each gear segment subtending the interiorangles of the equilateral triangle is 71/2. Because the numbers of gearteeth of each of the three gears between the intersection points a, b, cof the three gears is one-sixth the total number of gear teeth, in theembodiment shown in FIG. 12 each of the three gears will have a totalnumber of 45 teeth. In the embodiment of FIG. 12 each of the arcuatesections of gear teeth 292, 302 have 20 teeth and therefore each arcuatesection does not extend around one-half of the circumference of thegear. The difference in the number of the gear teeth of each arcuatesection 292, 302 and the number of gear teeth extending around one-halfof the circumference of the first and second gears 284, 294 ensures thatthe gear teeth of one of the arcuate sections will be completelydisengaged from the gear teeth 306 of the third gear 304 before the gearteeth of the other arcuate section come into engagement with the gearteeth 306 of the third gear.

In variations of the fourth embodiment of the gearing mechanism 262,should it be desirable to change the diameters and total numbers ofteeth surrounding the first, second and third gears, the numbers of gearteeth in the gear sections subtending the interior angles of theequilateral triangle ABC must be an integer and one-half of gear teethin order to ensure the synchronous rotation of the three gears and thealternating engagement of the two arcuate gear sections with the thirdgear. In each variation of the fourth embodiment of the mechanism, thetotal number of gear teeth surrounding the circumference of each gearwill equal six times the number of gear teeth (an integer and one-half)in the section of each gear subtending an interior angle of theequilateral triangle. For example, if the number of gear teeth in thegear section subtending an interior angle of the equilateral triangle is31/2, the total number of gear teeth will be 21. If the number of gearteeth in the gear section subtending an angle is 91/2, the total numberof gear teeth will be 57.

In operation, as the motor output shaft rotates at a constant speed in asingle direction, the worm gear 264 rotates the first driven gear 284about the center axis of its shaft 286 in a single direction (showncounterclockwise in FIG. 12) and at a reduced constant speed. Rotationof the first gear 284 about its shaft also imparts rotation to thesecond gear 294 in an opposite direction of rotation about its shaft 296(shown clockwise in FIG. 12) and at the same speed as the first gear.The gear teeth 288 surrounding the circumference of the first gear meshwith the gear teeth 298 surrounding the circumference of the second gearand the first and second gears rotate in opposite directions at the samespeed.

At alternating time periods, the gear teeth of the first gear arcuatesection 292 and the gear teeth of the second gear arcuate section 302will come into meshing engagement with the gear teeth 306 of the thirdgear. Because the teeth 306 of the third gear are elevated relative tothe gear teeth 288 extending around the circumference of the first gearand the gear teeth 298 extending around the circumference of the secondgear, the gear teeth of the third gear do not come into mesh with thesesets of gear teeth. As shown in FIG. 12, as the gear teeth of the firstarcuate section 292 come into engagement with the gear teeth 306 of thethird gear, the third gear is rotated in a clockwise direction togetherwith-the light assembly 256 about the pivot post 268. As the last geartooth of the first arcuate section of gear teeth 292 is coming out ofengagement with the gear teeth 306 of the third gear, the gear teeth ofthe second arcuate section 302 are coming into engagement with the gearteeth of the third gear. When the gear teeth of the second arcuatesection 302 come into engagement with the gear teeth 306 of the thirdgear, the gear teeth of the first arcuate section 292 are completelydisengaged from the gear teeth of the third gear. Engagement of the gearteeth of the second arcuate section 302 with the gear teeth 306 of thethird gear stops the rotation of the third gear and the light assemblyin the clockwise direction and immediately causes the third gear andlight assembly to rotate counterclockwise as viewed in FIG. 12. Becausethe number of gear teeth of the first and second arcuate sections 292,302 are the same, the alternating meshing engagement of the first andsecond arcuate sections of gear teeth with the gear teeth of the thirdgear cause the third gear and the light assembly to cycle through arcsegment oscillations at a substantially constant speed.

In the fourth embodiment of the invention 252, the size of the arcsegment swept by the signal light assembly 256 may be adjusted byemploying the third gear 304 as an idler gear in its position shown inFIG. 12 but without the light assembly, as shown in FIG. 15. The lightassembly would then be mounted on the base 254 adjacent the third, idlergear 304 in the same manner as described above. A fourth gear is mountedon the light assembly in mesh with the third, idler gear. By usingvarious different gears with different diameters and numbers of teeth asthe fourth gear, the size of the light assembly arc segment sweep isadjusted.

While the invention has been described by reference to specificembodiments, it should be understood that modifications and variationsof the invention may be constructed without departing from the scope ofthe invention defined in the following claims.

What is claimed is:
 1. An oscillating signal light mechanism, themechanism comprising:a base; at least one signal light assembly mountedon the base for rotation of the light assembly relative to the base; asource of motive power having a rotating output shaft; an oscillatorconfigured to oscillate the light assembly in response to rotation ofthe motive power source output shaft, the oscillator including a firstdriving wheel and a second driving wheel, the first and second drivingwheels being driven in opposite directions of rotation by the source ofmotive power, the first and second driving wheels alternately drivingthe light assembly in first and second directions, respectively.
 2. Themechanism of claim 1, wherein:the oscillator further includes a thirddriving wheel connected to the light assembly, the first and seconddriving wheels alternately contacting the third driving wheel to drivethe light assembly in the first and second directions.
 3. The mechanismof claim 2, wherein:the oscillator means further includes a fourthdriving wheel directly connected to the light assembly, the thirddriving wheel contacting the fourth driving wheel, thereby driving thelight assembly in the first and second directions.
 4. The mechanism ofclaim 3, wherein:the first, second, and third driving wheels are a samesize.
 5. The mechanism of claim 4, wherein:the fourth driving wheel isreplaceable with a fifth driving wheel having a size different from thefourth driving wheel to thereby vary a first distance the light assemblyis driven in the first direction and a second distance the lightassembly is driven in the second direction.
 6. The mechanism of claim 2,wherein:the first driving wheel has a first arcuate member extendingpartially around a circumference of the first driving wheel and thesecond driving wheel has a second arcuate member extending partiallyaround a circumference of the second driving wheel, and only the firstand second arcuate members alternately contact the third driving wheelto drive the light assembly in the first and second directions.
 7. Themechanism of claim 6, wherein:the first and second driving wheels have asame number of gear teeth extending around the circumferences of thefirst and second driving wheels.
 8. The mechanism of claim 6,wherein:the first and second arcuate members have a same number of gearteeth, and the third driving wheel has a first set of gear teethextending around a circumference of the third driving wheel for meshingwith the gear teeth of the first and second arcuate members.
 9. Themechanism of claim 8, wherein:the first driving wheel has a second setof gear teeth extending around the circumference of the first drivingwheel and the second driving wheel has a third set of gear teethextending around the circumference of the second driving wheel, and thefirst, second, and third sets of gear teeth have the same number of gearteeth.
 10. The mechanism of claim 9, wherein:the gear teeth of the firstand second arcuate members are coextensive with gear teeth of the secondand third sets of gear teeth, respectively.
 11. The mechanism of claim10, wherein:the first, second, and third driving wheels each have acenter axis about which they rotate, and the center axes of the first,second, and third driving wheels form the vertices of an equilateraltriangle.
 12. The mechanism of claim 11, wherein:lines extending betweenthe center axes of the first, second, and third driving wheels fromthree sides of the triangle, and an integer and one half of gear teethof each of the first, second, and third sets of gear teeth are boundedby the three sides of the triangle at any one time.
 13. The mechanism ofclaim 12, wherein:the oscillator further includes a fourth driving wheeldirectly connected to the light assembly, the fourth driving wheelhaving a fourth set of gear teeth extending around a circumference ofthe fourth driving wheel, the first set of gear teeth meshing with thefourth set of gear teeth, thereby driving the light assembly in thefirst and second directions.
 14. The mechanism of claim 13, wherein:thefourth driving wheel is replaceable with a fifth driving wheel having afifth set of gear teeth extending around a circumference of the fifthdriving wheel, the fourth and fifth sets of gear teeth having adifferent number of gear teeth.
 15. A rotatable light mechanism, themechanism including:a base; at least one light assembly mounted on thebase for rotation of the light assembly relative to the base; a sourceof motive power; a first wheel having a first arcuate member extendingpartially around a circumference of the first wheel, the first wheelbeing driven by the motive power source; and a second wheel connected tothe light assembly, the first arcuate member periodically contacting thesecond wheel to periodically rotate the light assembly.
 16. Themechanism of claim 15, further including:a third wheel directlyconnected to the light assembly, the second wheel contacting the thirdwheel, thereby periodically rotating the light assembly.
 17. Themechanism of claim 15, wherein:the first wheel is driven by the motivepower source in a single direction, and the first arcuate memberperiodically contacts the second wheel to periodically rotate the lightassembly in a first direction.
 18. The mechanism of claim 17,wherein:the first arcuate member has a first set of gear teeth, thesecond wheel has a second set of gear teeth extending around acircumference of the second wheel, and the first set of gear teethperiodically mesh with the second set of gear teeth to periodicallyrotate the light assembly in the first direction.
 19. The mechanism ofclaim 17, further including:a third wheel driven by a motive source andhaving a second arcuate member, the second arcuate member periodicallycontacting the second wheel to periodically rotate the light assembly ina second direction.
 20. The mechanism of claim 19, wherein:the firstwheel contacts the third wheel, thereby driving the third wheel in adirection opposite the single direction of the first wheel.
 21. Themechanism of claim 19, wherein:the first and second arcuate members havea substantially identical arcuate length.
 22. The mechanism of claim 19,wherein:the first arcuate member has a first set of gear teeth, thesecond arcuate member has a second set of gear teeth, and the secondwheel has a third set of gear teeth extending around a circumference ofthe second wheel and alternately meshing with the first and second setsof gear teeth.
 23. The mechanism of claim 22, wherein:the first wheelhas a fourth set of gear teeth extending around the circumference of thefirst wheel, the third wheel has a fifth set of gear teeth extendingaround the circumference of the third wheel, and the third, fourth, andfifth sets of gear teeth have the same number of gear teeth.
 24. Themechanism of claim 23, wherein:the gear teeth of the first and secondsets of gear teeth are coextensive with gear teeth of the fourth andfifth sets of gear teeth, respectively.
 25. The mechanism of claim 24,wherein:the first and second sets of gear teeth have the same number ofgear teeth.
 26. The mechanism of claim 24, further including:a fourthwheel directly connected to the light assembly, the fourth wheel havinga sixth set of gear teeth extending around a circumference of the fourthwheel, the third set of gear teeth meshing with the sixth set of gearteeth for rotating the light assembly in the first and seconddirections.
 27. The mechanism of claim 26, wherein:the fourth wheel isreplaceable with a fifth wheel having a seventh set of gear teethextending around a circumference of the fifth wheel, the sixth andseventh sets of gear teeth having a different number of gear teeth. 28.The mechanism of claim 19, further including:a fourth wheel directlyconnected to the light assembly, wherein the first, second, and thirdwheels are a same size, and the second wheel contacts the fourth wheelto rotate the light assembly in the first and second directions.
 29. Themechanism of claim 28, wherein:the fourth wheel is replaceable with afifth wheel having a size different from the fourth wheel to therebyvary an arc through which the light assembly rotates.
 30. A rotatablelight mechanism, the mechanism comprising:a base; at least one lightassembly rotatably mounted on the base; a first wheel operativelyconnected to the light assembly for periodically rotating the lightassembly in a first direction; a second wheel operatively connected tothe light assembly for periodically rotating the light assembly in asecond direction; the first and second wheels are alternatelyoperatively connected to the light assembly with the first wheel beingoperative connected to the light assembly when the second wheel is notoperatively connected to the light assembly and the second wheel beingoperatively connected to the light assembly when the first wheel is notoperatively connected to the light assembly; and, at least one source ofmotive power driving the first and second wheels.
 31. The mechanism ofclaim 30, wherein:the first and second wheels are driven by the samesource of motive power.
 32. The mechanism of claim 30, furtherincluding:a third wheel directly connected to the light assembly,wherein the first wheel periodically drives the third wheel toperiodically rotate the light assembly in the first direction, and thesecond wheel periodically drives the third wheel to periodically rotatethe light assembly in the second direction.
 33. The mechanism of claim32, further including:a fourth wheel contacting the third wheel, thefirst wheel periodically driving the fourth wheel to periodically rotatethe light assembly in the first direction and the second wheelperiodically driving the fourth wheel to periodically rotate the lightassembly in the second direction.
 34. The mechanism of claim 33,wherein:the first, second, and fourth wheels are a same size.
 35. Themechanism of claim 33, wherein:the third wheel is replaceable with afifth wheel having a size different from the third wheel to thereby varyan arc through which the light assembly rotates.